Carrie's Blog: What is a wake low? - WLOX.com - The News for South Mississippi

Carrie's Blog: What is a wake low?

This is where you can see the thunderstorm line starting to bow around the Baton Rouge area. This is where you can see the thunderstorm line starting to bow around the Baton Rouge area.
In two hours, the line makes its way into the Gulf of Mexico, and the wake low starts to form behind the rain. In two hours, the line makes its way into the Gulf of Mexico, and the wake low starts to form behind the rain.
SOUTH MISSISSIPPI (WLOX) -

Today, you probably heard us talk a lot about a wake low. This rare weather phenomenon resulted in the National Weather Service issuing a high wind warning through 2 p.m. for several of our counties. Our winds picked up and peaked a little after 2 p.m. after the rain moved out.

It's called a wake low because they generally develop in the wake of a storm. In the wake of the rain, a mesoscale low forms due to the lowering pressure, which actually tightens the pressure gradient and strengthens the wind. The sinking air behind the rain warms and forms the wake low.

Here's what happened: There was a mesoscale complex of storms that moved along a frontal boundary today. Within that complex, a strong line of thunderstorms developed and moved over Southeast Louisiana. That strong line of thunderstorms strengthened and bowed, which caused straight line wind damage in parts of New Orleans.

Here in South Mississippi, we had a good deal of rain and thunderstorms. This allowed temperatures to drop into the upper 50s here at WLOX. Within the next hour, temperatures rose 12 degrees through a process called adiabatic warming. That is when our winds peaked at 37 mph.

Think of adiabatic warming this way: As the air cools down, it begins to fall towards the surface of the Earth. As it sinks deeper into the atmosphere, the pressure from the weight of the air above pushes air molecules closer together, causing them to become more agitated and heating them up again. As a result, the temperature rises, even though no heat has been added. This process is referred to as adiabatic warming.

Wind is caused by differences in the atmospheric pressure. When a difference in atmospheric pressure exists, air moves from the higher to the lower pressure area, resulting in winds of various speeds.

It's the Earth's way of balancing itself.

A wake low is a type of gravity wave. Sometimes air in a stable environment can be forced to rise and naturally subside just like a wave in water. This downward air motion associated with a gravity wave can also trigger the development of a wake low.

These events are nearly impossible to forecast, because we need the real time data to confirm and then forecast. We also refer to this type of forecasting as ‘Now-casting.'

The National Weather Service can warn for the high winds after detecting certain patterns with the weather. Once it starts to see precipitation ending, pressure falling and higher winds, it notices the pattern of a wake low forming. Since there are no storms associated with these higher wind gusts, the NWS will often issue special weather statements, just like it did today.

The WLOX 24/7 Weather Team then relays that information to you on air, online and using social media tools like Facebook, Twitter, Instagram and Periscope.

You can like us on Facebook: Carrie Duncan WLOX Meteorologist, Meteorologist Joel Young, Meteorologist Wesley Williams and Tommy Richards

Follow us on Twitter: @carrieduncanwx, @JoelWLOX, @WesWilliamsII and @TommyWLOX

Also, you can download the new Periscope app and watch us behind the scenes: @carrieduncanwx and @joelwlox.

Copyright 2015 WLOX. All rights reserved.

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